1. Field of the Invention
This invention relates generally to the class of devices designed to accommodate persons with any disability in which sitting or rising from a seated position is difficult or in which certain restrictions for seat heights on chairs are recommended, including but not limited to patients who have undergone partial or total hip replacement.
2. Information Disclosure Statement
Currently there are three devices known to the inventor which address the need for an adjustable collapsible chair. No known device addresses the specific needs of a person with joint dysfunction. There are adjustable chairs which have legs with hollow sleeves and telescopic struts which are adjustable within the sleeve to shorten or lengthen the leg. In most cases, a flexible compression member is restrained within the hollow sleeve which is connected at one end to its respective strut and at the other to an adjustment means for selectively adjusting the length of the leg. Similarly, there are chairs which have adjustable back rests. These chairs are improvements over conventional chairs for individuals with particular needs.
However, there is no chair known to the inventor which is specifically designed to accommodate a person with a disability which renders the act of sitting or rising from a seated position difficult or in which certain restrictions as to seat height or seat pitch are necessary or recommended. For an individual with a partial or total hip replacement, for example, a chair must have adjustable height legs, a solid cushioned seat, and solid arm rests. Further, ideally, the seat of the chair should be positioned so that the hip does not exceed a 90.degree. angle with the lower extremities when the patient is seated. Following a hip replacement, within the hip joint the femoral head glides posteriorly as the lower extremity is flexed at the hip. The likelihood of dislocation is increased considerably when the angle created by the hip and the lower extremity exceeds 90.degree.. Following surgical repair, the muscle and the joint capsules are weakened increasing the risk or likelihood of dislocation. A patient must adhere to strict protocol which includes eliminating internal rotation of the hip joint or adduction of the lower extremity in an attempt to avoid dislocation and to decrease the risk of injury. Forward trunk flexion should also be avoided. This hip replacement protocol must be followed for three to six months after surgery.
Using an adjustable height chair will prevent the risk of dislocation as well as internal rotation and adduction of the lower extremities. The patient must sit in an armed chair at an appropriate height so that the patient's hip does not exceed a 90.degree. angle with his or her lower extremities. Most acceptable is for the patient's knees to be lower than the hip joint(s) when seated. This is not accomplished using a conventional chair or any typical seating arrangements.
There are adjustable chairs as mentioned above which are not specifically adapted for use by a person with a joint disability and are unfit for such use. In addition to those chairs, there are other pieces of adaptive equipment meant to assist total hip replacement patients with daily living such as adjustable bathtub seats, and equipment to convert toilet seats.
Conventional seating in many residences is completely inadequate to accommodate total hip replacement protocol. Absent an appropriate chair, it is necessary for total hip replacement patients to apply makeshift adjustments to their domestic furniture such as adding foam cushions to the seats, pillows to the back rests and blankets to the seat and backrest to increase the elevation of the seat of the chair or to adjust the angle of the hip when seated. Individuals may construct platforms to elevate a conventional chair. These makeshift adjustments are inefficient, ineffective, unsightly and can be dangerous to the patient or to other occupants of the home as they are often insecure and unstable. A chair perched on such a makeshift platform can easily slide off of the platform and further injure a seated patient. In addition, a patient with a disability might trip over a makeshift platform. Such bulky adjustments are inconvenient for family members who are not disabled.
Frequently patients who have had total hip replacement will add pillows to their seats to raise themselves to an acceptable height to maintain a greater than 90.degree. angle between their hip joint and their lower extremities. As the patient adds height by adding pillows to their seats, the arm rests remain at the same level and then offer no assistance in rising. Patients may injure themselves due to the weakened musculature and joint capsules as a result of surgery if they are unable to rely on firm arm rests for assistance in rising.
Clearly, what is needed, and hence, what would contribute to the state of the art, is a portable, yet sturdy, adjustable chair with appropriate adjustable seat height and arm rests to accommodate the problem posed by inadequate seating for hip replacement patients.
The following patents are known to the Inventor and are disclosed:
1. Condos U.S. Pat. No. 5,516,197 PA1 2. Wilson U.S. Pat. No. 5,494,333
Condos teaches an adjustable chair for use in a business setting. The legs are adjustable by flexible compression spring action and the partial backrest is adjustable, fore or aft for comfort. Both adjustments are made by levers. The chair is not suitable for a patient with hip dysfunction because it lacks arm rests and the base and backrest are not of sufficient size or stability. The chair is not portable, nor is it foldable or lightweight.
Wilson teaches a foldable lawn chair which has three adjustable leg extensions including leg extension locking means. The chair is not suitable for a patient with joint dysfunction as it does not have a solid seat and backrest. Also a patient would require four solid legs and wider arm rests for stability. It is not suitable as well because the rear leg would not be adjustable on a different plane than the front legs to create the required hip angle for a joint patient. The Wilson chair is designed for use on an incline or decline, such as a sporting event.